Propshafts are commonly employed for transmitting power from a rotational power source, such as the output shaft of a vehicle transmission, to a rotatably driven mechanism, such as a differential assembly. As is well known in the art, propshafts tend to transmit vibration while transferring rotary power. When the propshaft is excited at a harmonic frequency, vibration and noise may be amplified, creating noise and transmitting vibration that is undesirable to passengers riding in the vehicle. Thus, it is desirable and advantageous to attenuate vibrations within the propshaft in order to reduce noise within the vehicle passenger compartment.
Various devices have been employed to attenuate the propagation of noise from propshafts including inserts that are made from cardboard, foam, or resilient materials, such as rubber. The inserts that are typically used for a given propshaft are generally identical in their configuration (i.e., construction, size, mass and density) and are installed in the propshaft prior to the propshaft being installed in the vehicle. Integration of the propshaft assembly in this manner is advantageous in that it greatly simplifies the installation of the propshaft. Despite the various advantages, several drawbacks remain.
One such drawback is the susceptibility of current propshaft assemblies to the environment in which they are installed. More specifically, changing temperature and humidity levels cause a propshaft insert to swell or shrink. A loose propshaft insert poses myriad problems during installation. It is therefore, desirable to provide an improved propshaft insert that is able to withstand the changes in the environment in which it is installed.
Another such drawback is the necessary deformation of the propshaft insert when it is inserted into a propshaft. More specifically, the typical insert may need to be deformed to be inserted into the propshaft. The deformation of the propshaft insert may cause a reduction in its diameter. After installation, the insert may not return to its predetermined diameter, which that otherwise ensures a tight fit within the propshaft. It is desirable, therefore, to provide the propshaft insert with an improved configuration to ensure proper installation.